:root {
  --bg: #0b0d12;
  --panel: #151822;
  --text: #e8eaf0;
  --muted: #8992a6;
  --accent: #ff4d4f;
  --good: #3ddc84;
  --bad: #ff4d4f;
  --early: #ffb23d;
  --ring-idle: #2a2f3d;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  background: radial-gradient(circle at top, #1a1e29 0%, var(--bg) 60%);
  color: var(--text);
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  display: flex;
  justify-content: center;
  padding: 2rem 1rem;
}

.app {
  width: 100%;
  max-width: 480px;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.app__header { text-align: center; }
.app__header h1 { margin: 0 0 0.25rem; font-size: 1.8rem; letter-spacing: 0.02em; }
.app__subtitle { margin: 0; color: var(--muted); font-size: 0.9rem; }

.stage {
  position: relative;
  background: var(--panel);
  border-radius: 16px;
  padding: 2.5rem 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  min-height: 220px;
  overflow: hidden;
  transition: background-color 0.15s ease;
}

.stage__ring {
  width: 96px;
  height: 96px;
  border-radius: 50%;
  border: 6px solid var(--ring-idle);
  transition: border-color 0.1s ease, transform 0.1s ease;
}

.stage[data-state="window"] .stage__ring {
  border-color: #ffffff;
  transform: scale(1.08);
}
.stage[data-state="hit"] .stage__ring { border-color: var(--good); }
.stage[data-state="miss"] .stage__ring,
.stage[data-state="late"] .stage__ring { border-color: var(--bad); }

.stage__message {
  font-size: 1.2rem;
  font-weight: 600;
  text-align: center;
}
.stage[data-state="hit"] .stage__message { color: var(--good); }
.stage[data-state="miss"] .stage__message,
.stage[data-state="late"] .stage__message { color: var(--bad); }

.stage__detail {
  color: var(--muted);
  font-size: 0.9rem;
  min-height: 1.2em;
}

.controls {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
}

.btn {
  background: var(--panel);
  color: var(--text);
  border: 1px solid #2a2f3d;
  border-radius: 10px;
  padding: 0.65rem 1.25rem;
  font-size: 0.95rem;
  cursor: pointer;
  transition: border-color 0.15s ease, background-color 0.15s ease;
}
.btn:hover { border-color: var(--muted); }
.btn--primary {
  background: var(--accent);
  border-color: var(--accent);
  font-weight: 600;
}
.btn--primary:hover { filter: brightness(1.08); }
.btn.is-binding { border-color: var(--early); color: var(--early); }

.settings {
  background: var(--panel);
  border-radius: 16px;
  padding: 1rem 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}
.settings__row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  font-size: 0.9rem;
}
.settings__row select,
.settings__row input[type="range"] {
  accent-color: var(--accent);
}

.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.75rem;
}
.stat {
  background: var(--panel);
  border-radius: 12px;
  padding: 0.75rem 0.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
}
.stat__label { color: var(--muted); font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.05em; }
.stat__value { font-size: 1.1rem; font-weight: 700; }

.footnote {
  text-align: center;
  color: var(--muted);
  font-size: 0.78rem;
  margin: 0;
}